Twin Bushing Track Chain Cartridge

ABSTRACT

A cartridge assembly for a track chain is disclosed. The cartridge assembly includes a pin that has a lubricant channel therein. The pin is accommodated in an inner bushing that also has a channel extending therethrough for accommodating the pin. The pin extends beyond either end of the inner bushing. The pin and inner bushing are partially disposed in an outer bushing that also has a channel for accommodating the pin in inner bushing. The ends of the inner bushing and pin extend beyond the ends of the outer bushing. First and second inserts are disposed at either end of the inner bushing. The first and second inserts are disposed between the outer bushing and a pair of opposing collars which are disposed on the ends of the pin beyond the inserts and beyond the ends of the inner bushing. The inserts and collars each include seals. The seals of the collars are supported by one or more thrust rings as opposed to the inserts or partially by the inserts.

TECHNICAL FIELD

An endless track chain for a track type vehicle is disclosed, and, moreparticularly, a cartridge assembly that acts as a joint for relativerotation between links of the track chain is disclosed.

BACKGROUND

Track type work machines typically have a sprocket, an idler, and atrack chain assembly. During use of the work machine, the sprocketrotates and engages the track chain assembly, thereby causing the trackchain assembly to rotate around a path defined by the sprocket and theidler. The rotation of the track chain assembly causes the machine to bepropelled over the ground so as to perform various work functions.

As shown in U.S. Pat. No. 7,850,256, track chain assemblies generallyinclude a pair of parallel chains, with each parallel chain being madeup of a series of track links. Track chain assemblies further include aseries of cartridges that include bushings, pins, collars, seals andinserts. The cartridges are interposed between and connected to thelinks of the parallel chains. The cartridges and the entrained tracklinks cooperate to form a number of track joints which allow thenecessary movement of the track links during use of the track chainassembly, for example, when the track chain assembly rotates about thesprocket and the idler.

SUMMARY OF THE DISCLOSURE

In one example, a cartridge assembly for a track chain is disclosed. Thecartridge assembly includes a pin that defines a longitudinal access andthat has a lubricant channel. The pin includes a first and secondopposing ends. The cartridge assembly includes an inner bushing havingfirst and second ends and a channel extending therethrough for rotatablyaccommodating a portion of the pin disposed between the first and secondopposing ends of the pin. The cartridge assembly further includes anouter bushing having first and second ends and a channel extendingtherethrough for accommodating a portion of the inner bushing disposedbetween the first and second ends of the inner bushing. The cartridgeassembly also includes first and second inserts. Each insert has achannel extending therethrough for accommodating opposing portions ofthe inner bushing that extend beyond the outer bushing. The first insertengages the first end of the outer bushing and the second insert engagesthe second end of the outer bushing. The cartridge assembly alsoincludes first and second collars, each having a channel extendingtherethrough for accommodating portions of the pin that extend beyondthe inner bushing. And, the cartridge assembly may include a firstthrust ring disposed between the first collar and the first insert and asecond thrust ring may be disposed between the second collar and thesecond insert.

The first insert and first collar may be joined together or be formed asa single part. Similarly, the second insert and second collar may bejoined together or be formed as a single part. Also, the thrust ringsmay be separate parts or be formed as part of the inserts, collars,inner bushing or a combination thereof.

In another example, a track chain in disclosed which includes aplurality of cartridge assemblies. Each cartridge assembly includes apin that defines a longitudinal access and it has a lubricant channel.The pin includes first and second opposing ends. An inner bushingincludes first and second ends and a channel extending therethrough forrotatably accommodating a portion of the pin disposed between the firstand second opposing ends of the pin. An outer bushing is included thathas first and second opposing ends and a channel extending therethroughfor accommodating a portion of the inner bushing disposed between thefirst and second opposing ends of the inner bushing. The track chainalso includes first and second inserts. Each insert has a channelextending therethrough for accommodating opposing portions of the innerbushing that extend beyond the outer bushing. The first insert engagesthe first end of the outer bushing while the second insert engages thesecond end of the outer bushing. Each cartridge assembly of the trackchain also includes first and second collars. Each collar has a channelextending therethrough for accommodating portions of the pin that extendbeyond the inner bushing. Each cartridge assembly of the track chainalso includes a first thrust ring disposed between the first collar andthe first insert and, similarly, a second thrust ring disposed betweenthe second collar and the second insert. The first and second thrustrings each include inner and outer radial faces. The outer radial facesof the first and second thrust rings support first and second sealsrespectively. The inner radial face of the first and second thrust ringsengage one of the pin or inner bushing. The first collar of eachcartridge assembly of the track chain is accommodated in a first link.The second collar is accommodated in a second link. The first insert isaccommodated in a third link and the second insert is accommodated in afourth link.

In yet another example, a method for providing stiffness to a cartridgeassembly of a track chain is disclosed. The method includes providing apin defining a longitudinal access and having a lubricant channel. Thepin includes first and second opposing ends. The method also includesinserting the pin into an inner bushing having first and second ends anda channel extending therethrough for rotatably accommodating a portionof the pin with the first and second opposing ends of the pin extendingbeyond the first and second opposing ends of the inner bushingrespectively. The method also includes inserting the pin an innerbushing into an outer bushing having first and second opposing ends andthe channel extending therethrough for accommodating a portion of theinner bushing with the pin and with the inner bushing extending beyondthe first and second ends of the outer bushing. The method furtherincludes coupling first and second inserts over opposing portions of theinner bushing that extend beyond the outer bushing and coupling thefirst insert to the first end of the outer bushing and coupling thesecond insert to the second end of the outer bushing. The method alsoincludes coupling a first thrust ring to the pin and the first end ofthe inner bushing and coupling a second thrust ring to the pin in asecond end of the inner bushing. The method also includes coupling thefirst and second collars to the first and second thrust ringsrespectively and to portions of the pin that extend beyond the innerbushing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side plan view of a track type machine that can incorporatethe track chain cartridges disclosed herein.

FIG. 2 is a partial sectional view of a disclosed cartridge assembly fora track chain.

FIG. 3 is a sectional view of yet another disclosed cartridge assemblyfor a track chain.

FIG. 4 is another partial sectional view of a disclosed cartridgeassembly for a track chain.

FIG. 5 is yet another partial sectional view of a disclosed cartridgeassembly for a track chain.

DETAILED DESCRIPTION

While the prior art track chain assemblies articulate around thesprocket and the idler, and thereby allow the work machine to bepropelled over the ground, the prior art track chain assemblies sufferfrom several drawbacks. For example, the prior art track chainassemblies tend to be mechanically complex and are prone to structuralproblems. Specifically, the cartridge assemblies (bushings, pins,collars, seals and inserts) are difficult to manufacture and assembleand, further, lack sufficient axial stiffness to ensure a long workinglife. Therefore, a track chain assembly which overcomes theabove-mentioned drawbacks is needed.

Referring to FIG. 1, a track type machine 500 includes a machine body512, having a drive sprocket 520 mounted to a side thereof. A trackchain 514 extends about the drive sprocket 520, as well as a rear idler518 and a front idler 519. The track chain 514 includes a plurality oflinks 515 movably coupled to two other links 515 via a sleeve bearingcartridge assembly 10. A plurality of track rollers 517 may be coupledwith work machine body 512 and rotate against track chain 514 in aconventional manner. The machine 500 may include identical track chains,drive sprockets and idlers on opposite sides thereof, in a conventionalmanner. The machine 500 is illustrated as a relatively large “highdrive” tractor, however, it should be appreciated that this disclosureis not thereby limited, and any of a wide variety of track type machinesmight be designed according to this disclosure.

FIG. 2 is a partial sectional view of a disclosed cartridge assembly 10.The cartridge assembly 10 includes a pin 11 that includes a lubricantchannel 12 extending therethrough for accommodating lubricant anddelivering lubricant to various other channels in the cartridge assembly10, such as those shown at 13-15 in FIGS. 2 and 3. The pin 11 includesan opening 16 which is sealed with a plug assembly 17.

In the cartridge assembly 10 shown in FIG. 2, the pin 11 is accommodatedwithin an inner bushing 18. The inner bushing 18 and pin 11 are thenaccommodated within an outer bushing 19. An insert 22 accommodates thepin 11 and inner bushing 18 and also engages an end 23 of the outerbushing 19. The insert 22 includes a recess 24 that accommodates a seal25. The insert 22 is disposed between the outer bushing 19 and a collar26. The collar 26 accommodates the end 27 of the pin 11 and alsoincludes a recess 28 for accommodating a seal 29.

A more complete illustration of a cartridge assembly 100 is illustratedin FIG. 3. The pin 11 includes first and second opposing ends 31, 27respectively. Each end 31, 27 of the pin 11 includes an opening 32, 16respectively that is sealed with a plug assembly 33, 17. The lubricantchannel 12 serves as a reservoir for lubricant and also deliverslubricant through the channel 15 to the inner bushing 18 and through thechannels 13, 14 to the outer bushing 19. The inner bushing 18 includesfirst and second opposing ends 36, 37 and the outer bushing 19 includesfirst and second opposing ends 38, 39 respectively.

In the cartridge assembly 100 shown in FIG. 3, the first and secondinserts 41, 22 respectively engage the first and second opposing ends38, 39 of the outer bushing 19 respectively and are also disposed on topof the inner bushing 18 near the first and second opposing ends 36, 37respectively. The first and second inserts 41, 22 are also axiallysandwiched between the outer bushing 19 and the first and second collars40, 26 respectively or, more specifically, the first and second inserts41, 22 are sandwiched between the outer bushing 19 and the first andsecond thrust rings 43, 44 and the first and second seals 45, 29respectively. The first and second thrust rings 43, 44 support the seals45, 29 and avoid the necessity of designing the inserts 41, 22 toaccommodate or support the outer seals 45, 29. Similarly, the first andsecond inner seals 46, 25 are disposed in recesses 48, 24 in the inserts41, 22 and engage the first and second opposing ends 38, 39 of the outerbushing 19 as shown in FIG. 3. Similarly, the first and second outerseals 45, 29 are accommodated in recesses 52, 28.

One problem associated with prior art cartridge assemblies 10 for trackchains is the use of the inserts 41, 22 to accommodate and/or supportthe outer seals 45, 29. Normally such designs reduce the thickness ofthe inner bushing 18 which can compromise the structural integrity ofthe inner bushing 18. Compromising the structural integrity of theinserts 41, 22 can also compromise the inner box stiffness, which canlead to link walking, shoe bolt loosening and link cracking. A lack ofstrength in the inserts 41, 22 also compromises the axial stiffness of acartridge assembly 10. Therefore, FIGS. 2-5 illustrate four variations,all of which preserve the integrity of the first and second inserts 41,22 and provide improved inner box stiffness, reduced shoe boltloosening, reduced link cracking and increased axial stiffness.

Returning to FIG. 2, the cartridge assembly 10 includes a single thrustring 144 that engages the second opposing end 37 of the inner bushing18. The single thrust ring 144 supports the seal 29 as shown. The insert22 is not utilized for supporting the seal 29 in a radial direction, noris there any need for an extension of the insert 22 for supporting theseal 29. In FIG. 3, the cartridge assembly 100 also includes singlethrust rings 43, 44, but which are thicker than the thrust ring 144shown in FIG. 1.

Turning to FIGS. 4-5, the cartridge assembly 200 of FIG. 4 may featureinner and outer thrust rings 244, 344 respectively, or one thick thrustring 244/344. Again, the insert 22 is not used or needed to support theseal 29. Turning to FIG. 5, instead of the thrust ring 444 engaging thepin 11 the thrust ring 444 rides on top of the inner bushing 18. In thecartridge assembly 300 shown in FIG. 5, the end 137 of the inner bushing18 has been extended so it passes through the thrust ring 444.

The insert 22 and collar 24 may be joined together or be formed as asingle, unitary part. Similarly, the insert 41 and collar 40 may bejoined together or be formed as a single part. Also, the thrust rings43, 44, 144, 244/344, 444 may be separate parts or be formed as part ofthe inserts 41, 22, collars 40, 26, inner bushing 18 or a combinationthereof.

INDUSTRIAL APPLICABILITY

The four cartridge assemblies 10, 100, 200, 300 are illustrated thatprovide improved inner box stiffness, reduced link walking, reduced shoebolt loosening, reduced link cracking and improved axial stiffness. Andimproved these advantages, without being bound to any particular theory,may be the result of the use of thrust rings 43, 44, 144 for supportingthe outer seals 45, 29 as opposed to using a portion of the inserts 41,26 for the same function.

A method for providing stiffness to a cartridge assembly 10 of a trackchain 514 is also disclosed. The method includes providing a pin 11 thathas a lubricant channel 12 and first and second opposing ends 31, 27.The pin 11 is inserted into an inner bushing 18 that also has first andsecond opposing ends 36, 37. The inner bushing 18 also has a channel 15extending therethrough for rotatably accommodating a portion of the pin11 with the first and second opposing ends 31, 27 of the pin 11extending beyond the first and second opposing ends 36, 37 of the innerbushing 18. The pin 11 and the inner bushing 18 are then inserted intoan outer bushing 19 which also has first and second opposing ends 38,39. The opposing ends 36, 37 of the inner bushing 18 and the opposingends 31, 27 of the pin 11 both extend beyond the opposing ends 38, 39 ofthe outer bushing 19. The first and second inserts 41, 22 are coupledover opposing portions of the inner bushing 18 that extend beyond theouter bushing 19 and the first insert 41 is coupled to the first end 38of the outer bushing 19 and the second insert 22 is coupled to thesecond end 39 of the outer bushing 19. A first thrust ring 43 is coupledto the pin 11 and the first end 36 of the inner bushing 18. Similarly, asecond thrust ring 44 is coupled to the pin 11 and the second end 37 ofthe inner bushing 18.

1. A cartridge assembly for a track chain, comprising: a pin defining alongitudinal axis and having a lubricant channel, the pin includingfirst and second opposing ends; an inner bushing having first and secondends and a channel extending therethrough for rotatably accommodating aportion of the pin disposed between the first and second opposing endsof the pin; an outer bushing having first and second opposing ends and achannel extending therethrough for accommodating a portion of the innerbushing disposed between the first and second opposing ends of the innerbushing; first and second inserts, each having a channel extendingtherethrough for accommodating opposing portions of the inner bushingthat extend beyond the outer bushing, the first insert engaging thefirst end of the outer bushing, the second insert engaging the secondend of the outer bushing; first and second collars, each having achannel extending therethrough for accommodating portions of the pinthat extend beyond the inner bushing; and first and second thrust rings,the first thrust ring disposed between the first collar and the firstinsert, the second thrust ring disposed between the second collar andthe second insert.
 2. The cartridge assembly of claim 1 furtherincluding a first seal disposed between the first collar and firstinsert and a second seal disposed between the second collar and secondinsert.
 3. The cartridge assembly of claim 1 wherein the first thrustring includes a pair of first thrust rings, one disposed inside theother and the second thrust ring includes a pair of second thrust rings,one disposed inside the other.
 4. The cartridge assembly of claim 1wherein the first and second thrust rings are disposed on top of theinner bushing.
 5. The cartridge assembly of claim 1 wherein the firstand second thrust rings each include opposing ends, one end of the firstthrust ring engaging the first end of the inner bushing and one end ofthe second thrust ring engaging the second end of the inner bushing. 6.The cartridge assembly of claim 5 wherein the other end of the firstthrust ring engages the first collar and the other end of the secondthrust ring engages the second collar.
 7. The cartridge assembly ofclaim 1 wherein the first and second thrust rings each include opposingends, one end of the first thrust ring engaging the first insert and theother end of the first thrust ring engaging the first collar, and oneend of the second thrust ring engaging the second insert and the otherend of the second thrust ring engaging the second collar.
 8. Thecartridge assembly of claim 1 wherein the first and second opposing endsof the pin each accommodate a plug.
 9. The cartridge assembly of claim 1further including a first seal axially sandwiched between the firstcollar and the first insert and a second seal axially sandwiched betweenthe second collar and the second insert, the first seal being radiallysandwiched between the first collar and the first thrust ring, thesecond seal being radially sandwiched between the second collar and thesecond thrust ring.
 10. The cartridge assembly of claim 1 furtherincluding a first seal axially sandwiched between the first collar andthe first insert and a second seal axially sandwiched between the secondcollar and the second insert, the first seal being radially sandwichedbetween the first collar and the inner bushing, the second seal beingradially sandwiched between the second collar and the inner bushing. 11.The cartridge assembly of claim 1 wherein the first collar has anaxially facing inner face with at least one recess for accommodating afirst seal and the first thrust ring, and the second collar has anaxially facing inner face with at least one recess for accommodating asecond seal and the second thrust ring.
 12. The cartridge assembly ofclaim 1 wherein the first collar has an axially facing inner face withat least one recess for accommodating a first seal, the first thrustring and the first end of the inner bushing, and the second collar hasan axially facing inner face with at least one recess for accommodatinga second seal, the second thrust ring and the second end of the innerbushing.
 13. The cartridge assembly of claim 1 further including firstand second seals axially sandwiched between the first and second collarsand first and second inserts respectively, the first and second sealseach including an inner radial surface that does not engage the firstand second inserts respectively.
 14. The cartridge assembly of claim 1further including first and second seals axially sandwiched between thefirst and second collars and inserts respectively, the first and secondseals each including an inner radial surface that engages one of thefirst and second thrust rings respectively.
 15. A track chaincomprising: a plurality of cartridge assemblies, each including a pindefining a longitudinal axis and having a lubricant channel, the pinincluding first and second opposing ends; an inner bushing having firstand second opposing ends and a channel extending therethrough forrotatably accommodating a portion of the pin disposed between the firstand second opposing ends of the pin; an outer bushing having first andsecond opposing ends and a channel extending therethrough foraccommodating a portion of the inner bushing disposed between the firstand second opposing ends of the inner bushing; first and second inserts,each having a channel extending therethrough for accommodating opposingportions of the inner bushing that extend beyond the outer bushing, thefirst insert engaging the first end of the outer bushing, the secondinsert engaging the second end of the outer bushing; first and secondcollars, each having a channel extending therethrough for accommodatingportions of the pin that extend beyond the inner bushing; and first andsecond thrust rings, the first thrust ring disposed between the firstcollar and the first insert, the second thrust ring disposed between thesecond collar and the second insert, wherein the first and second thrustrings each include inner and outer radial faces, the outer radial facesof the first and second thrust rings supporting first and second sealsrespectively, the inner radial faces of the first and second thrustrings engaging one of the pin or the inner bushing; and the first collarbeing accommodated in a first link, the second collar being accommodatedin a second link, the first insert being accommodated in a third linkand the second insert being accommodated in a fourth link.
 16. The trackchain of claim 15 further including a first seal axially sandwichedbetween the first collar and the first insert and a second seal axiallysandwiched between the second collar and the second insert, the firstseal being radially sandwiched between the first collar and the firstthrust ring, the second seal being radially sandwiched between thesecond collar and the second thrust ring.
 17. The track chain of claim15 further including a first seal axially sandwiched between the firstcollar and the first insert and a second seal axially sandwiched betweenthe second collar and the second insert, the first seal being radiallysandwiched between the first collar and the inner bushing, the secondseal being radially sandwiched between the second collar and the innerbushing.
 18. The track chain of claim 15 further including first andsecond seals axially sandwiched between the first and second collars andinserts respectively, the first and second seals each including an innerradial surface that does not engage the first and second insertsrespectively.
 19. The track chain of claim 1 further including first andsecond seals axially sandwiched between the first and second collars andinserts respectively, the first and second seals each including an innerradial surface that engages one of the first and second thrust ringsrespectively.
 20. A method for providing stiffness to a cartridgeassembly of a track chain, the method comprising: providing a pindefining a longitudinal axis and having a lubricant channel, the pinincluding first and second opposing ends; inserting the pin into aninner bushing having first and second opposing ends and a channelextending therethrough for rotatably accommodating a portion of the pinwith the first and second opposing ends of the pin extending beyond thefirst and second opposing ends of the inner bushing respectively;inserting the pin and inner bushing into an outer bushing having firstand second opposing ends and a channel extending therethrough foraccommodating a portion of the inner bushing with the pin and with theinner bushing extending beyond the first and second opposing ends of theouter bushing; coupling first and second inserts over opposing portionsof the inner bushing that extend beyond the outer bushing and couplingthe first insert to the first end of the outer bushing and coupling thesecond insert to the second end of the outer bushing; coupling a firstthrust ring to the pin and the first end of the inner bushing andcoupling a second thrust ring to the pin and the second end of the innerbushing; coupling first and second collars to the first and secondthrust rings respectively and to portions of the pin that extend beyondthe inner bushing.